silver mica caps code

tubbytwo · 1st December 2004, 05:47 PM

I was given a bag of misc silver mica caps. Going through them to sort I found mostly 43 pF. (Marked 430) Now I know the third number is the number of zeros but I was told on these (CDE & SMI) caps the value is marked as is, ah, no multiplier and is a 430pF. Ok, then why do I also have 181 and 271 that would be 180 and 270....1 being the number of zeros. To double check, I looked at a radio I was supposed to have 100pF caps on, sure enough they were marked SMI 100 and the invoice from AES confirmed I ordered 100s (they don't stock 10s)
Several Google searches show the 3rd number being the multiplier! Can anyone confirm the numbering system.

markp · 1st December 2004, 11:51 PM

The standard is that the third number is the number of zeros, but not everyone complies to the standard! I've found that if the number is followed by pF then it is the actual value of the cap, but not always. '220pF' written on the cap is usually 220 not 22pF.

Apex Jr · 2nd December 2004, 12:58 AM

Also with mil-spec parts the last number is the multiplier
IE: newer silver mica's CMO5181J is a 180 Pfd at 5%
F = 1% ... G = 2% ... J = 5% ... K = 10% and M = 20%
Steve @ Apex Jr.

1st December 2004, 05:47 PM	#1
tubbytwo diyAudio Member Join Date: Nov 2004 Location: Burbank CA	silver mica caps code I was given a bag of misc silver mica caps. Going through them to sort I found mostly 43 pF. (Marked 430) Now I know the third number is the number of zeros but I was told on these (CDE & SMI) caps the value is marked as is, ah, no multiplier and is a 430pF. Ok, then why do I also have 181 and 271 that would be 180 and 270....1 being the number of zeros. To double check, I looked at a radio I was supposed to have 100pF caps on, sure enough they were marked SMI 100 and the invoice from AES confirmed I ordered 100s (they don't stock 10s) Several Google searches show the 3rd number being the multiplier! Can anyone confirm the numbering system. __________________ -Mike

1st December 2004, 11:51 PM	#2
markp diyAudio Member Join Date: Oct 2003 Location: L.A., CA	The standard is that the third number is the number of zeros, but not everyone complies to the standard! I've found that if the number is followed by pF then it is the actual value of the cap, but not always. '220pF' written on the cap is usually 220 not 22pF. __________________ If it sounds good... it is good!

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2nd December 2004, 12:58 AM	#3
Apex Jr diyAudio Member Join Date: Jun 2002 Location: La Crescenta Calif	Also with mil-spec parts the last number is the multiplier IE: newer silver mica's CMO5181J is a 180 Pfd at 5% F = 1% ... G = 2% ... J = 5% ... K = 10% and M = 20% Steve @ Apex Jr.

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